Synthesis and properties of polyurethane coatings: the effect of different types of soft segments and their ratios

Abstract

Polyurethane (PU) coatings were prepared using siloxane polyol [poly(dimethyl siloxane), PDMS], polyether polyol [poly(propylene oxide glycol), PPG], and polyester polyol [poly(tetramethylene adipate glycol), PTAd]. The PTAd/PPG ratio was altered, whereas the PDMS content was fixed during PU synthesis. The structural elucidation of the synthesized PU was performed by Fourier transform infrared (FT-IR), 1H NMR, 13C NMR, and 29Si NMR spectroscopic techniques. The PU-film surface was characterized by X-ray Photoelectron Spectrometer and atomic force microscopy techniques and it was found that the surface smoothness depended on the PPG/PTAd ratio. The PU melting temperature, crystallinity, mechanical properties (tensile strength and Young’s modulus), and adhesive strength were also depended on the PPG/PTAd ratio. The adhesive strength to poly(vinyl chloride) of the coating with the proper polyol ratio (PTAd 12.50 mol% and PPG 16.67 mol%) was almost unaffected after immersion (three months) in artificial salt.